Neuropeptide Y potentiates noradrenaline-induced contraction through the neuropeptide Y Y-1 receptor

To elucidate which neuropeptide Y receptor subtype is responsible for the neuropeptide Y-induced potentiation of the noradrenaline-evoked contraction in human omental arteries we used antisense oligodeoxynucleotide (Antisense), the new selective neuropeptide Y Y-1 receptor antagonist, BIBP3226 {(R)-N2-(diphenylacetyl)-N-[(4-hydroxyphenyl)methyl]-D-arginine-amide} and the reverse transcriptase polymerase chain reaction (RT-PCR). Neuropeptide Y significantly potentiated the noradrenaline-induced contraction in non-incubated vessels (pEC(50) 6.4 +/- 0.2 vs. 5.9 +/- 0.2) and in vessels incubated with 1 mu M Sense oligodeoxynucleotide (Sense) (pEC(50) 6.0 +/- 0.1 vs. 5.6 +/- 0.2). In vessels incubated with 1 mu M Antisense the potentiating effect of neuropeptide Y was completely abolished. BIBP3226 (1 mu M) inhibited the neuropeptide Y-induced potentiation in human omental arteries (pEC(50) 5.8 +/- 0.3 vs. 6.4 +/- 0.2). Finally, messenger RNA for the neuropeptide Y Y-1 receptor was detected using RT-PCR. On the basis of our results we conclude that the neuropeptide Y-induced potentiation of the noradrenaline-induced contraction is mediated by the neuropeptide Y Y-1 receptor.